基于DEM-CFD耦合方法的水合物与砂颗粒运动分析

采用离散元素法(discrete element method,DEM)和计算流体力学(computational fluid dynamics,CFD)的耦合方法,对海底水合物中砂颗粒和水合物颗粒运动进行了研究。利用球形颗粒沉降模拟实验验证了耦合方法的可行性,分别分析了单个砂颗粒和单个水合物颗粒运动过程中颗粒位置、速度、受力及角速度的变化规律。结果表明:砂颗粒向容器底部沉降,在到达底部时发生碰撞,同时颗粒发生旋转;水合物颗粒向上运动,颗粒没有发生旋转。最后对颗粒群进行了模拟仿真,结果表明,DEM-CFD耦合法能够模拟大量颗粒运动的复杂流动,并且能从微观尺度分析颗粒受力和运动情况,对水合物颗粒和砂颗粒运动的研究提供了一种可靠有效的方法。

Analysis of hydrate and sand particle movement based on DEM-CFD coupling method

The movement of hydrate and sand particles in submarine hydrate mining is still unclear. Therefore, in this study, the coupling method of the discrete element method (DEM) and computational fluid dynamics (CFD) is adopted to study the movement of hydrate and sand particles at the seabed. To verify the proposed method, the settling of spherical particles is simulated and compared with experimental findings. The feasibility of the proposed method is illustrated. Moreover, numerical simulations of a single sand particle and a single hydrate particle are performed using the DEM-CFD coupling method. Various particle positions, velocities, forces, and angular velocities are analyzed during particle movement. Simulation results show that the sand particles settle at the bottom of the container and collide when they reach the bottom while rotating simultaneously. The hydrate particles float upward without rotation. Finally, a numerical simulation of a particle swarm is performed in a closed container to show that the DEM-CFD coupling method can simulate complex flow with a large number of particles and analyze the particle force and movement at the microscopic scale. This study provides a reliable and effective method for multiphase flow research on hydrate and sand particles.